1. Field of the Invention
The invention relates to a system for reconstituting beverages using superheated constituting liquid to simultaneously effect a sterilization or pasteurization of the beverages. More particularly, the invention relates to a system of the aforementioned type wherein the reconstituting process can be intermittently interrupted and restarted again without any risk of product degradation or loss of aseptic conditions.
2. Description of Related Art
Various processes for reconstituting and pasteurizing beverages have been described. Reconstitution and pasteurization have been carried out separately. In such processes the heat treatment is carried out indirectly by heating the reconstituted beverage in a tank or directly by injecting high-temperature steam into the beverage. Alternatively, the reconstituted beverage can also be passed as droplets into a jet of high-temperature steam. Indirect heat treatment has the disadvantage of creating undesirable deposits on the tank walls or a caramelization phenomenon. Direct heat treatment has the disadvantage of producing a product having a quantity of excess water which must subsequently be removed.
In an attempt to overcome the disadvantages associated with separated reconstituting and pasteurizing steps, processes have been developed wherein both steps are carried out simultaneously. For example, processes have been developed wherein water is heated to a temperature such that it produces a reconstituted product whose temperature is similar to that at which pasteurization is to be carried out. In accordance with this process superheated water and concentrate continuously flow into a mixing chamber where the reconstituted beverage is aseptically produced.
In processes of this type it is important that all piping and equipment downstream of the mixing chamber remain sterile. Maintaining such aseptic conditions can be problematical where the system is shutdown. During a shutdown sterilization of concentrate in the mixing chamber may be incomplete. The temperature of the mixing chamber will drop during the shutdown. When the system is restarted, unsterile product can emanate from the mixing chamber and pass downstream to contaminate the system. This problem is particularly apparent in the case of a mixing chamber having a large volume.
Attempts have been made to solve the problem of contamination after a shutdown by introducing concentrate into the mixing area from a pipe which runs upward. In this way, during a shutdown, the force of gravity tends to urge concentrate away from the sterile mixing zone. However, this effort has not been entirely successful. For example, in the case of a pulp-containing concentrate like orange juice pulp may float on the concentrate in the area of the mixing zone to contaminate the zone.
Another problem which can occur during a shutdown is degradation of product in the mixing chamber caused by prolonged exposure of the concentrate to high temperatures. There is therefore a need for a system wherein the temperature of the mixing chamber can be lowered during a shutdown and then raised again before restarting the system so as to avoid both product degradation during the shutdown and loss of aseptic conditions when the system is restarted.
Accordingly, it is an object of the present invention to provide a process for reconstituting beverages which can be interrupted and restarted without adversely affecting the sterility of the system.
It is a further object of the invention to provide an apparatus for reconstituting beverages having a mixing chamber whose temperature can be controlled during a shutdown of the apparatus so as to avoid product degradation caused by prolonged exposure of the beverage to high temperatures.
It is yet a further object of the invention to provide an apparatus for reconstituting beverages having a mixing chamber which can be adjusted so as to minimize its volume during a shutdown of the apparatus thereby allowing the chamber to be flushed with a small amount of water and permitting cooling and reheating of the chamber without the risk of altering the flavor or other qualities (e.g., Brix) of the product.
It is a further object of the invention to provide an apparatus of the type described above wherein a constant holding time may be provided for a product in the mixing chamber notwithstanding variations in the flow rate.